condition mean min max ZT0-3 15.75 15.75 15.75 ZT4-7 18.3 18.3 18.3 ZT8-11 14.6 14.6 14.6 ZT12-15 18.1 18.1 18.1 ZT16-19 20.7 20.7 20.7 ZT20-23 16.0 16.0 16.0